How Does Machine Espresso Work?

The machine espresso uses precision pressure, and a filtering system that is awe-inspiring to make the coffee you enjoy. How exactly does it work?

To make an Espresso machine small hot water is forced under high pressure through finely ground coffee. The process is similar to that of making drip coffee. However, the pressure is the main difference.

The Group Head

As the name implies the group head is where you insert your portafilter when making espresso. It distributes water into the portafilter, and regulates the pressure of extraction. There are a variety of types of group head each with its unique advantages and disadvantages. Some are specifically designed for stability in temperature, while others are specifically designed to handle pre-infusion. Others are built to control the lever. Some are a combination, such as the E61. This is a popular choice among baristas because it offers multiple advantages in one package.

As you can see from the above photo, the group head is fitted with a variety of notches. You place your portafilter inside these notches, and then twist the head to lock it. A gasket of rubber is situated in the notches to create a seal while you insert your portafilter. The notches on the head permit an exact position of the portafilter which is crucial for an even extraction.

The group head not only lets you to insert your portafilter easily but also maintains the temperature at a constant level. This is accomplished by cycling hot water around the portafilter, and through the brew-basket, making sure that the temperature is at the right level to extract the coffee. This is important because just a few degrees could make the difference between a good and great espresso.

The Pump

Motorized pumps in espresso machines rotary provide nine atmospheric bar pressure required to extract espresso. This differs from manual piston machines that rely on levers. This pressure is generated by pumping water through a heat exchanger and then through the ground coffee.

Pumps are generally cheaper and last longer than piston-driven machines. However, both kinds of machines are susceptible to degrading due to overuse and insufficient cleaning. Pumps are also more complicated mechanically, which can increase prices of even simpler models.

Certain espresso machines eliminate the pump completely and instead employ steam pressure to create espresso. The drawback of this is that the boiler that produces steam also raises the temperature of water until it reaches boiling which can cause over-extraction. They also have to continually rebuild their pressure between cups. This takes energy and time.

A majority of espresso machines use the rotary or vibration pump, which has a vibration model that uses a vibrating disc to create pressure and rotating models that push hot water through the grounds under high speed. Both machines produce great espresso, but rotary machines are more stable, quieter and less likely to break.

The Boiler

The boiler heats the water to the ideal temperature to extract. The resultant steam then reaches the portafilter which holds the ground espresso and is then pumped into the cup. During this process the steam generates enough pressure to push the grounds of the coffee through. This creates a crema on the top of the espresso. This is one of the hallmarks of a great espresso.

There are three kinds of espresso machines, each with distinct pumps and brew temperature. There are also different ways in which the brew could be controlled as well as the dimensions of the cup the machine can produce.

The earliest espresso machines were steam-based. They used one boiler to create steam and brew, however the pressure they were able to create was minimal - two bars of atmospheric pressure maximum. This led to the coffee tasting bitter and burnt. This is why Milanese manufacturers Luigi Bezzerra and Desiderio Pavoni created the modern espresso machine.

The most commonly used espresso machine is a semiautomatic that has an electric pump. These are the images people have when they think of an best cheap espresso machine maker. Semi-automatic machines require you to grind and tamp the beans by yourself however the pump controls the water flow and pressure. This is an excellent solution that combines human control with mechanized consistency.

The Filter

Espresso machines usually use a filter that separates the grounds of the coffee from hot water. The filter is also an essential element of the machine's temperature control, since it stops overheating.

It also improves flavor, as a filter allows for a more prolonged bloom time. This allows beans to release their nuances and gives the chance for better extraction.

However it is crucial to remember that even a top filter can produce a bad cup of coffee, since the quality of the beans and extraction is essential.

It's in this area that the magic occurs. This is the reason why espresso tastes so delicious. The grouphead, also called the brew head, is where the portafilter (the container you place the ground coffee in) sits when you're making espresso.

In an espresso machine that is driven by steam, hot water is heated in an airtight container to create steam. This is then pushed through the grounds at a high pressure. These kinds of machines are usually less expensive and simpler to maintain than pump-driven models. They are however limited in their ability to create the ideal conditions for brewing since they only operate with 1-1.5 bar of pressure. The perfect shot requires 9-10 bars.

In recent years, compressed air pump-driven espresso machines have become more popular. They use an air compressor to force hot water into the ground and are more mobile than electric steam-driven espresso machines.